fsmonitor: access repo.root
There is no repo._root. It looks like fsmonitor has
been busted since this access was introduced in
ab1900323b1 in July 2019!
Differential Revision: https://phab.mercurial-scm.org/D7207
#require serve
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[255]
$ test -d copy
[1]
$ "$PYTHON" "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg clone http://localhost:$HGPORT/foo copy2
abort: HTTP Error 404: * (glob)
[255]
$ killdaemons.py